Anterior Cervical Instrumentation Systems, Methods and Devices

ABSTRACT

Anterior cervical instrumentation systems, methods, and devices are disclosed. Systems may facilitate immobilizing or providing support for the cervical portion of the vertebral column of a patient. A device may comprise a plate having two channels located in a proximal to distal direction, and may further comprise at least one aperture. The device may further comprise attachment elements such as attachment cross-links and spacer cross-links, and fasteners. The plate and the attachment elements may be secured to the vertebrae by passing fasteners through apertures and channels. The length of the plate, position and number of the attachment cross-links, position and number of spacer cross-links and degree of movement may be intraoperatively selected by the surgeon to provide an optimal application and procedural outcome. Uniform components of the devices and systems allow for a more streamlined and simplified method of treating spinal conditions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application claiming priorityunder 35 U.S.C. §120 to U.S. patent application Ser. No. 13/405,926,filed 27 Feb. 2012, which claims priority to U.S. patent applicationSer. No. 12/554,220, filed 4 Sep. 2009, which issued as U.S. Pat. No.8,147,529, which claims priority under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. No. 61/094,340 filed 4 Sep. 2008,all of which are hereby incorporated in their entireties as if fully setforth herein.

TECHNICAL FIELD

Embodiments of the present invention relate to implantable surgicalstabilization systems, devices, and methods for use in spinal surgery,and particularly to systems, methods, and devices that stabilize thecervical spine or other osseous structures.

BACKGROUND

Fusion of spinal vertebrae is often necessary to relieve debilitatingpain or to correct a deformity. Cervical spinal fusion is oftenprescribed for patients suffering from degenerative disk disease whosesymptoms may include neck pain of discogenic origin with degeneration ofthe disk confirmed by patient history and radiographic studies, traumaincluding fractures, tumors, deformity such as kyphosis, lordosis orscoliosis, pseudoarthrosis, or failed previous fusions.

Spinal surgical fusion is the process of bringing together two or morevertebrae under conditions whereby the vertebrae fuse together to form aunitary member of the spinal column. When vertebrae are fused, e.g.,with bone grafts, graft extenders, or interbody spacers such asinterbody cages or boxes (collectively termed “grafts” herein), it isdesirable to stabilize the fused vertebrae using an apparatus such as aplate to fixate one cervical vertebra to another to promote fusionacross motion segments. In carrying out the procedure, the members mustbe brought together under conditions that are critically controlled toprevent infection, maintain alignment of opposing members, and allow forthe stress in the bone that is generated as the healing process matures.Immobilization is an important requirement during this healing process.

Another common spinal ailment is the degeneration of an intervertebraldisc caused by trauma, disease, and/or aging. A degeneratedintervertebral disc may have to be partially or fully removed from aspinal column. Partial or full removal of an intervertebral disc maydestabilize a spinal column. Destabilization of a spinal column mayalter the natural separation distance between adjacent vertebrae.Maintaining a natural separation distance between vertebrae may helpprevent pressure from being applied to nerves that pass betweenvertebral bodies. Excessive pressure applied to the nerves may causepain and/or nerve damage. During a spinal fixation procedure, a spinalimplant may be inserted in a space created by removal or partial removalof an intervertebral disc between adjacent vertebrae. A spinal implantmay maintain the height of the spine and restore stability to the spine.Intervertebral bone growth may fuse the implant to adjacent vertebrae.

A spinal implant may be inserted during a spinal fixation procedureusing an anterior, lateral, or posterior spinal approach. A discectomymay be performed to remove or partially remove a defective and/ordamaged intervertebral disc. A discectomy creates a disc space for aspinal implant. After a discectomy, a spinal implant may be insertedinto the disc space. One or more spinal implants may be inserted betweena pair of vertebrae. Spinal implants may be inserted into disc spacesprepared between more than one pair of vertebrae during a spinal fusionprocedure.

A spinal plate may be coupled to vertebrae after insertion of one ormore spinal implants. A spinal plate may stabilize the vertebrae andinhibit back out of the spinal implant from between vertebrae. A spinalplate may share a compressive load applied to one or, more spinalimplants inserted between vertebrae. Fasteners, such as bone screws, maycouple the spinal plate to vertebrae. Spinal plates may stabilizesections of cervical spine and/or sections of lumbar, spine.

The process of bone healing has been widely studied. Micro fractures,once thought to be negative events, are now seen as part of the naturalprocess of bone remodeling and occur within bone in the course ofeveryday wear and tear. In the early stage of these cycles, boneresorption is first accomplished by osteoclasts. This is followed by newbone formation by osteoblasts over the latter part of each cycle.Osteoblasts serve a critical role in new bone formation, filling in thebony cavity in areas of bone remodeling with bone matrix. Osteoblastsare further known to release cytokines to attract osteoclasts.Osteoclasts serve to release proteases, which act to dissolve bonemineral matrix, collagen, and clear away damaged bone. Osetoclasts alsoreleases matrix-bound growth factors and may serve as a chemo attractantfor osteoblasts. The process of bone healing is currently believed to bea continual cycle, in which the body's response to microfractures andstress injuries within healing bone actually serve to strengthen healingultimately and produce more solid bone.

What is needed are systems, methods and devices such as a plating systemto repair bone fractures or to stabilize separate bony structures andallow them to fuse into a single item that may incorporate or harnessthe elements of the natural bone healing process. What are needed aresystems, methods and devices that promote optimal fusion at a graft,particularly at cervical vertebrae. Further, methods, systems anddevices that utilize a minimum number of parts and which may be easilycustomized intraoperatively by the surgeon are also needed.

SUMMARY

The present invention is directed to spinal instrumentation systems,methods and devices. The present invention comprises plating systems foruse in spinal treatments, including, but not limited to, the cervicalspine. Embodiments of the present invention are directed to anteriorcervical instrumentation systems. Such systems may facilitateimmobilizing or providing support for the cervical portion of thevertebral column of a patient. Such systems are composed of plates andscrews for aligning and holding vertebrae in a desired position relativeto one another. The systems may be “stand alone” as instrumentation isapplied only to the anterior portion of the vertebral column (cervicalvertebrae), or the systems may include other devices or compositionssuch as instrumentation on the posterior vertebral column. The systems,methods and devices allow a surgeon to modify and customize systemcomponents intraoperatively for optimal fit.

The present invention comprises systems, methods and devices comprisingan implantable device for affixing to the anterior side of vertebrae,such as cervical vertebrae, for stabilizing the spinal column. Systemsand devices of the present invention comprise a plate having an anteriorsurface and a posterior surface. A plate may comprise two parallelelongate channels extending from the distal end of the plate to theproximal end of the plate. Each of the channels forms an elongatedopening through plate. A plate may further comprise at least oneaperture, which may be centrally located, or at least one aperture atboth the distal and proximal ends, and for stability reasons, maycomprise two apertures at both the distal and proximal ends. Theapertures may function in attaching the plate to a spinal vertebra usingfasteners, such as screws. For example, apertures may be round, oval orrounded rectangular or combinations of these or others in shape. Thesystems may comprise a plurality of different length plates, whichallows a surgeon the flexibility to select the desired length plate pre-or intraoperatively.

Systems and devices of the present invention may further compriseattachment elements for attaching the plate to one or more spinalvertebrae or for stabilizing the plate device. For example, a system anddevice may comprise a plurality of elements referred to herein ascross-linking elements. Cross-linking elements comprise at least twotypes of elements which may be similar in design, but differ infunction. The two types of cross-linking elements comprise attachmentcross-links and spacer cross-links and, for example, each may be a smallbar that is as long as the plate is wide, with a defined width, that hastwo apertures, and each aperture may have the diameter of the aperturesof the plate, and may also be sized so that a fastener, such as a screw,is sized to pass through the cross-linking aperture and also passthrough the channel. Cross-linking element apertures may be located nearboth ends of a cross-linking element so that the apertures of thecross-linking elements align with each of the two channel openings in aplate.

The attachment elements comprise fasteners, elements for directlyattaching the plate or attachment cross-links to the vertebrae, orattaching spacer cross-links to the plate, and such fasteners maycomprise pins, dual head pins or screws. Fasteners may be sized to passthrough the apertures of the cross-linking elements, the channels, andthe apertures of the plates. Fasteners comprise a pin having two heads,wherein each head is spaced apart so that each pin head may enter aplate channel or two adjacent apertures.

Methods of the present invention comprise methods of spinal treatment,including treatment of the cervical spine. Methods comprise approachingthe cervical spine from an anterior position. Using a template of aplate of the present invention, the exact location and placement of aplating system and device on the patient is determined. The template maybe used on the exposed vertebrae or on x-rays or other visualizations ofthe spinal area. The size of plate to be used, the number cross-linkingelements and attachment sites, where the attachment elements are to beplaced through the plate apertures and the cross-link apertures isdetermined. Thus, the size of the plate and cross-link placement mayindividualized for the patient during the surgical procedure.

The appropriately sized plate may then be placed over the anteriorportion of the vertebrae and anchored in place by the placement offasteners, such as screws, through the at least one aperture, such asthose found on the proximal and distal ends of the plate. The plate maybe held in place with a temporary fastener, including but not limitedto, a dual-headed pin. The pin is temporary in that the pin is placedthrough the plate to temporarily anchor the plate to the bone(s), forexample to examine placement of the plate and alignment of the pin, andthen the pin is removed. The pin may serve as a guide for bone screwswhich anchor the plate in place.

The proximal and distal apertures of a plate can be of several types.The first type may have the apertures of the same size and be round inshape, which allows for semi-constrained movement at the screw heads.Another type may have proximal and distal apertures that would beslightly elongated in the vertical axis, referred to herein as oval, toallow for translational movement at the proximal and distal ends of theplate. Another type may have proximal and distal apertures that would beelongated in the vertical axis, referred to herein as roundedrectangular, to allow for translational movement at the proximal anddistal ends of the plate.

One or more attachment cross-links may be placed on the anterior side ofthe plate in the predetermined locations for attachment of the plate tothe vertebrae, and attached to the vertebrae. For example, the plate andattachment cross-link may be attached to a spinal vertebra by passing ascrew through each of the apertures of the cross-link and the parallelchannels of the plate, and into the bone. The attachment cross-link maybe fixed in position relative to the bone, but may move relative to theplate as the screws move in the parallel channels of the plate.Alternatively, the attachment cross-links may be spring loaded to lockit in position relative to the plate. The attachment cross-link may bepositioned relative to the plate at any point along the length of thechannels. Consequently, the surgeon may custom fit the location of theattachment cross-link to the bone because the position is not limited bypredetermined screw holes in the plate.

Once one or more attachment cross-links are coupled to the vertebralbones, spacer cross-links may be fastened to the plate. The spacercross-links do not attach to vertebrae, but fill the channel space onthe device where the attachment cross-links are not present and functionto stabilize the device. The entire length of the channels of the platethat are not occupied by the attachment cross-links may be filled withthe spacer cross-links until there remains little or no open space inthe channels of the plate. The spacer cross-links may be attached to theplate using a variety of fasteners, including, but not limited to, ahole-to-hole clamp or a screw head, or a short screw. The distancebetween the cross-links may be determined by the surgeon to create arange of travel of the attachment cross-link to provide a desired degreeof subsidence. In this manner, the attachment cross-link attached to thebone may be locked in place relative to the plate or may have apredetermined degree of movement. The fasteners for attaching the platedevice to the bone, such as screws, may be maintained in place by usinglocking heads or other designs known in the art.

An aspect of the present invention comprises systems, methods anddevices wherein the plates may be provided in multiple lengths, but theapertures of the plates and the cross-linking elements, and the channelsized openings are uniform and allow for the use of the same size andstyle fastener head, such as the same screw head, for attachment ofcross-linking elements, though the lengths of the fasteners may be avariety of lengths. This allows the surgeon to use one instrument, suchas the same screw driver implement, to attach the plate to the vertebraeand to stabilize the device. The size, such as length and width of thecross-linking elements, is uniform and may be used with any lengthplate. This uniformity allows for a more simplified system for thesurgeon to use, and for fewer tools to be needed in the operatingtheater.

An exemplary embodiment of the invention can be a vertebralstabilization device that can comprise an elongate plate. The plate canhave a distal end and a proximal end and can comprise a first elongatechannel and a second elongate channel. The first and second elongatechannels can be substantially parallel and extend along at least aportion of the plate between the distal end and the proximal end,wherein each of the first and second elongate channels can have aninterior surface. At least a portion of the interior surfaces cancomprise a plurality of channel grooves. The plate can further comprisea first attachment cross-link, the first attachment cross-link can havea first aperture and a second aperture, and the first and secondapertures can be configured to be aligned with the first and secondelongate channels. In an embodiment, at least a portion of at least oneouter surface of the first attachment cross-link can comprise aplurality of cross-link grooves adapted to cooperatively engage theplurality of channel grooves of the interior surface of at least one ofthe first and second elongate channels.

These and other features as well as advantages, which characterizevarious aspects of the present invention, will be apparent from areading of the following detailed description and a review of thedrawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A illustrates an exemplary embodiment of a plate of the presentinvention.

FIG. 1B illustrates an exemplary embodiment of a plate of the presentinvention.

FIG. 1C illustrates an exemplary embodiment of a plate of the presentinvention.

FIG. 1D illustrates a side view an exemplary embodiment of a plateattached to a region of the spinal column.

FIG. 2 illustrates an exemplary embodiment of a system having aplurality of plates.

FIG. 3A illustrates three embodiments of cross-linking elements.

FIG. 3B illustrates an embodiment of a dual-headed pin.

FIG. 3C illustrates an embodiment of an offset dual-headed pin.

FIG. 3D illustrates an embodiment of placement of an offset dual-headedpin.

FIGS. 4A and B illustrate a top view of a plate and cross-linkingelements of an exemplary embodiment of the present invention.

FIG. 5 illustrates a side view of an exemplary embodiment of the systemattached to a spinal column.

FIG. 6A illustrates a top view of a plate and attachment cross-links ofan exemplary embodiment of the present invention.

FIG. 6B illustrates an embodiment of attachment cross-links of anexemplary embodiment of the present invention.

FIG. 6C illustrates a top view of a plate of an exemplary embodiment ofthe present invention.

FIG. 6D illustrates a bottom view of a plate and attachment cross-linksof an exemplary embodiment of the present invention.

FIG. 7A illustrates a top view of a plate and attachment cross-links ofan exemplary embodiment of the present invention.

FIG. 7B illustrates a top view of a plate of an exemplary embodiment ofthe present invention.

FIG. 7C illustrates bottom view of a plate and attachment cross-links ofan exemplary embodiment of the present invention.

FIG. 8 illustrates a top view of a plate, attachment cross-links and anextension adapter of an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention comprises methods, systems and devices fortreatment of spinal vertebrae, such as cervical vertebrae. The presentinvention comprises implantable devices comprising plates and attachmentelements that allow for aligning and maintaining adjacent vertebrae,including but not limited to, cervical vertebrae, in a selected spatialrelationship. The present invention may be used in spinal fusionmethods.

The present invention comprises anterior cervical plating systems anddevices that allow for the intersegmental compression of the spinalsegment, such as compression of the adjacent vertebrae and the fusiongraft in the disc space between the adjacent vertebrae, in lordosis, andwhere desired, multisegmental compression. For example, a device of thepresent invention comprises a plate, attachment elements comprisingcross-linking elements comprising attachment cross-links and spacercross-links, and fasteners, elements for directly attaching the plateand cross-linking elements to the bone, or attaching cross-linkingelements to the plate, including, but not limited to, screws anddual-headed pins. For example, a system of the present inventioncomprises a plurality of plates of various lengths, and uniformly sizedattachment elements and fasteners with uniform head design, and havingmultiple lengths. The invention further comprises tools and instrumentsused with such systems and devices in methods of spinal treatment suchas drills, taps, screw drivers and the like.

Systems and devices of the present invention comprise a plate, which maybe provided in a length that is sufficient to span a disc space and tooverlap, at least in part, at least two adjacent cervical vertebrae. Theanterior and posterior surfaces of a plate may be the same or may bedifferent, in that one of the surfaces, such as the posterior surfacewhich faces the vertebrae, may be textured and/or treated to induce bonegrowth or aid in attachment or stability. The plate, and other elementsof the systems and devices, may be made of the same or differentmaterials, such as steel, titanium, plastics, ceramics, or otherbiocompatible materials that have the structural strength and durabilityto withstand the cyclical loading associated with long term fixation.Materials that are also compatible with visualization systems, such asfluoroscopy or MRI, are also contemplated by the present invention. Theplate and other elements may also comprise bioresorbable materials, bonein-growth materials, and/or growth promoting materials. For example,such bioresorbable, bone in-growth, or bone growth promoting materialsmay be found on surfaces of the plate and/or attachment elements such asscrews. A plate of the present invention may be curved transverse to thelongitudinal axis to conform to the anterior surface of a vertebrae, ormay be curved along the longitudinal axis to conform to the lordoticcurvature between the vertebrae, or may not be curved at all, or may bemade of a material so that a surgeon or other personnel may curve theplate at the time of surgery, or may be made of a material that does notallow curving by a surgeon or other personnel.

A plate of the present invention comprises an anterior surface and aposterior surface and the two surfaces may be the same or different overthe whole surface or a part of the surface areas. For example, theposterior surface, which directly faces the vertebrae surface, may betextured or coated with a material so as to encourage bone growth. Forexample, the anterior surface may be textured so as to allow betterpurchase of the attachment elements. The plate comprises a distal endand a proximal end. An aperture may be found on one or both of thedistal or proximal ends, or may be located in a central position at thedistal or proximal ends, or between the channels at one or both of theproximal or distal end areas, or in a midline position.

An example of a plate of the present invention comprises at least oneaperture on both the proximal and the distal ends, and may furthercomprise at least two apertures on at least one of the proximal ordistal ends, or at least two apertures on both the proximal and distalends. The apertures may be the same size diameter or may havedifferently sized diameters. An example of the present inventioncomprises a plate having at least two apertures at both the proximal anddistal ends that are of the same size diameter. An example of thepresent invention comprises a plate have at least one aperture at themidline of the plate equidistant between the channels. An example of thepresent invention comprises a plate having one or more apertures withthe same size diameter or differently sized diameters. An example of thepresent invention comprises a plate having one or more apertures on theat least the proximal or distal end(s) where the apertures are longer invertical length than the screw head to allow for true translationalmovement at both ends.

Where the one or more apertures on the distal and proximal ends of theplate are round or where the aperture allows for little adjustment forscrew placement, the movement of the plate is based uponsemi-constrained movement at the screw heads. Where the one or moreapertures on the distal and proximal ends of the plate are enlongated sothat the vertical length is longer than the horizontal length, as inoval or rounded rectangular shaped apertures, there may be movement ofthe embedded screws in relation to the plate to allow for translationalmovement. Where the one or more apertures on the distal end aredifferent from the one or more apertures on the proximal end, forexample wherein rounded apertures are present on the proximal end toprovide semi-constrained movement and one or more elongated or ovalapertures are found at the distal end, translational movement isprovided. Similarly, apertures in the cross-linking elements also allowfor semi-constrained or translational movement depending on the shape ofthe aperture. The movement may be constrained by use of apertures havinga particular shape that locks a screw tightly with the aperture. Forexample, the screw head and the aperture shape may be complementary sothat a tight junction is formed between the screw head and the top ofthe aperture. For example, the aperture may be shaped like a star orother figure into which the screw head or a locking head fits exactlyand constrains the movement at that location.

A plate of the present invention comprises at least two channels thatare open from the anterior to the posterior surfaces, and which formopenings that traverse a substantial portion of the length of the plate.The at least two channels run from an area near an aperture found at thedistal end to an area near an aperture found at the proximal end, orwhere there are no apertures on the ends of the plate, the channels runfrom near the proximal end to near the distal end. The width of achannel may be the same or different size as the diameter of an apertureof a plate. An example of the present invention comprises a plate havingtwo channels having widths of the channel openings that are the same asthe diameter of the apertures of the plate, wherein the apertures of theplate have the same sized diameter.

Devices and systems of the present invention comprise attachmentelements. Attachments elements comprise cross-linking elements andfasteners, elements that interact intimately with the bone or thatattach cross-linking elements to a plate, such as screws and dual-headedpins. Cross-linking elements comprise attachment cross-links and spacercross-links. Cross-linking elements are rectangular shaped bars that fittransversely across a plate, and for example, may be as long as a plateis wide. Cross-linking elements may have no apertures or at least oneaperture. For example, a cross-linking element has two apertures thatare located so that an aperture is on each end of the cross-linkingelement, so that when the cross-linking element is placed on theanterior surface of a plate, the cross-linking apertures align with thetwo channels of the plate. The apertures of a cross-linking element mayhave the same or different diameter as that of the plate aperture(s),and/or may have the same or different diameter as that of the width ofthe plate channels. An example of the present invention comprises adevice having apertures of the same diameter, and having channel widthsthat are the same as the aperture diameters of the plate and thecross-linking elements. An example of the present invention comprises adevice having apertures of the same diameter, and having channel widthsthat are the same as the aperture diameters or widths of thecross-linking elements.

An attachment cross-link is used for attaching the device to a bone,such as a vertebra. The attachment cross-link may have as many aperturesas the plate has channels, for example, an attachment cross-link has twoapertures that will align with two channels of a plate. An attachmentcross-link is placed transversely across the anterior surface of a plateand an aperture of the attachment cross-link provides an opening thoughthe cross-linking element and on through the channel opening of theplate. An attachment cross-link length may be shorter or longer than thewidth of the plate. An attachment cross-link may be as thick as orthinner than the thickness of the plate. An attachment cross-link may betextured on either its anterior or posterior surface, for example, sothat texturing on its posterior surface meshes with texturing on theanterior surface of the plate, or either or both surfaces of theattachment cross-link may have a material that promotes bone in growth,bone growth, or aids in healing soft tissues. It is contemplated by thepresent invention that in use, an attachment cross-link is held with thedevice by the passing of a fastener such as a screw or pin through eachof the aperture(s) of the attachment cross-link, through the channelopening of the plate and into the bone of the vertebrae. The head of thescrew would engage with the attachment cross-link and the other end ofthe screw would be secured in the bone, and lock the attachmentcross-link to the plate and the device to the bone.

A spacer cross-link is used for stabilizing the device. A spacercross-link is placed transversely across the plate in the area of thechannels where the attachment cross-link(s) is not present. In use, thespacer cross-links occupy the area between the proximal and distal endsof the plate where the channels are and provide stability to the device.A spacer cross-link may have as many apertures as the plate haschannels, for example, a spacer cross-link has two apertures that willalign with two channels of a plate. A spacer cross-link is placedtransversely across the anterior surface of a plate and the twoapertures of the spacer cross-link provide an opening though thecross-linking element and on through the channel opening of the plate. Aspacer cross-link may be shorter or longer than the width of the plate.A spacer cross-link may be as thick as or thinner than the thickness ofthe plate. A spacer cross-link may be textured on either its anterior orposterior surface, for example, so that texturing on its posteriorsurface meshes with texturing on the anterior surface of the plate, oreither or both surfaces of the spacer cross-link may have a materialthat promotes bone in growth, bone growth, or aids in healing softtissues. It is contemplated by the present invention that in use, aspacer cross-link is held with the device by the passing of a fastenersuch as a short screw through each of the aperture(s) of the spacercross-link, or by use of a spring loaded mechanism that clamps thespacer element to the plate, or by other methods of attachment. Forexample, the head of a short screw would engage with the anteriorsurface of the spacer cross-link and the other end of the screw may beflush with the posterior surface of the plate, which would lock thespacer cross-link to the plate.

A spacer cross-link may or may not be the same size, as in length,width, and/or thickness, as the attachment cross-link. For example, asystem and device of the present invention comprise attachmentcross-links and spacer cross links that are the same length, width andthickness, and have the same number and size apertures. Such a systemand device would comprise only one type of cross-linking element thatcould be used for attachment and for spacing purposes. Such a systemwould use a fastener such as a screw, having only one diameter head,which may be provided in longer and shorter lengths, depending on theuse of the cross-linking element, long for attachment and shorter forspacing. This would provide for use of only one type of screw driver.Such a system and device provides for uniform components to be used inimplanting the device, and simplifies the methods and decisionsperformed by the surgeon.

Attachment elements of the present invention comprise fasteners,elements that interact intimately with the bone, or that attachcross-linking elements to a plate, such as bone screws, screws, bolts,pins, dual-headed pins, rivets, projecting elements, cements, plastics,or other components that may attach the plate to the bone orcross-linking elements to a plate. A description is provided hereincomprising screws, but the invention is not necessarily limited to theuse of only screws for this purpose. An aspect of the present inventionprovides for a device that allows for the placement of screws enteringbone have sufficient angular freedom relative to the plate, in thevariability of the axis of screw placement in the superior, inferior,medial and lateral directions. In the present invention, the surgeon mayinsert the bone screws into the vertebrae as to best to fit the anatomyof the individual patient, or multi-axial placement of a screw, such asat any angle up to 10-20 degrees from normal to the surface of theplate. The bone screws may be of a length that is sufficient forunicortical or bicortical placement. The bone screws may be selftapping, or may be inserted after tapping or drilling procedures, orafter pin placement and removal. The bone screws may be locked intoplace with locking mechanisms known to those skilled in the art, such asa locking cap, locking ring, or a threaded cap. The screws used in thepresent invention for bone attachment may all be identical or different.For example, the screws used in the present invention are identical inlength, width, and head design. For example, the screws used withattachment cross-links are identical to screws used with spacercross-links in width and head design, but not in length.

Methods of the present invention comprise use of the systems and devicesdisclosed herein for treatment of spinal disease, damage or otherconditions and pathologies. For example, a common approach for thesurgical management of cervical disk disease is anterior cervical spinalfusion. The procedure for cervical spinal fusion is initiated byincising a small opening in the front of the neck. There is minimaltrauma to the neck tissues. The damaged disk and/or bone spurs may beremoved anterior to the spinal cord. This approach allows for minimalspinal or cord traction. Frequently, if there is significant spinal cordcompression or if there is more than one disk level involved, a smallplate is affixed on the anterior surface of the cervical vertebrae toprovide greater permanent stability.

In a method of the present invention for anterior cervical spinalfusion, the following steps are performed. A template of a plate of thepresent invention may be used to determine placement of the plate, theattachment cross-links, the number of spacer cross-links needed, and theplacement and angular location of the screws. A template is a replica ofa plate of a particular length, and may be of a material that allows forvisualization of the area under the template, i.e., may be transparent,and may be capable of having measurements written on it. The templatemay be used once the spinal vertebrae are exposed or may be used withx-rays or other visualization data. While the device components arebeing assembled based on the determinations made from the templateplacement, operating personnel may be preparing the vertebrae forinsertion of screws, such as by pre drilling sites or tapping.Alternatively, no template is used and alternatively sized plates areused to make the determinations of placement and components.

A method of the present invention comprises temporary attachment of theplate to the vertebral bones. A plate may be held in place on theanterior spine temporarily by the use of pins, including, but notlimited to, dual headed pins. The plate may be held in position using aninstrument that allows for the insertion of temporary pins in aperturesfound at both the distal and proximal ends of a plate, or in theproximal and distal ends of elongated channels in plates that do nothave end apertures. An inserter allows for a dual-head pin to be placedthrough the aperture or channel with visualization techniques, such asfluoroscopy. Use of the dual-headed pin and visualization allows thesurgeon to determine the correct angle of placement for the screws thatwill follow the pins, to determine the correct length of the screws, andwhether the plate is centrally and correctly aligned along the long axisof the vertebral bodies.

The dual-headed pins as disclosed herein are a single construct with aninserter that causes the pin heads to be placed in a parallelrelationship. The placement of the pins under fluoroscopy aids incorrect alignment in the sagittal and coronal planes. If the plate iscorrectly aligned coronally (not tilted to one side vertically), withlateral imaging, the dual pins will appear as one pin. If there is no orpoor coronal alignment, two pins will show. If the pins are alignedcoronally, but are not equally placed in the vertebral bodies, thenunder lateral visualization, the pins will be parallel, but one pin willappear to be deeper than the other pin.

The dual-headed pin, or any other pin known in the art, are contemplatedto be of a sufficient size such that the placement in the bone andremoval creates a tract or path for the bone screw or other fastener tofollow. A pin or dual-headed pin may be disposable, in that it may beused only once, or may be reusable as long as the pin is structurallysound.

As an example, the surgeon can align the plate first and then select thebest angle to place the pins under direct fluoroscopy. Pins, such as thedual-headed pin, may have pin heads of several lengths, ranging fromabout 8 to about 28 mm, from about 10 to about 25 mm, from about 12 toabout 20 mm, from about 12 to about 16 mm, from about 15 to about 20 mm.Use of the pins allows for the estimation of the length of the bonescrews to be used. The nonparallel angles of entry may prevent exactmeasurement of the length needed by the screws, but the presentinvention provides for a close approximation of the longest screws thatcan be safely used to attach the plate.

When elongated apertures are used, a dual-headed pin would be located inthe upper portion of the upper (proximal) apertures, and the lowerportion of the lower (distal) apertures, which would allow fortranslational dynamic movement once the device is assembled on vertebralbodies with screws or other attachment elements in place. Forconvenience, proximal and distal are in relation to the head, with itemscloser to the head being proximal.

To allow for true translational movement, the dual headed pin could havea 1-2 mm off-set on one side. This off-set would allow for pin placementin the upper end of the plate to have the off-set turned down and forpin placement in the lower end of the plate to have the off-set turnedsuperior. The pins will fit into the upper portion of the upper(proximal) apertures and the lower portion of the lower (distal)apertures insuring the correct placement to allow translational dynamicmovement. See FIG. 3C for a side view of a dual head pin with an offset,wherein the pin heads are offset from the central plane of the dual headpin. The b indicates the side of the pin with the offset, as does theribbing on the handle 355, to indicate in which direction the pin headsare offset. See FIG. 3D for an example of placement of two dual headedpins with offset pin heads. In FIG. 3D, only one distal and proximalapertures are shown with pin placement and direction of the pin,indicated by a and b, are shown. The body of the pin is not shown. Inpractice, the dual headed pin with offset pin heads would be placed inthe apertures, or in elongated channels, with the pins in the upperportion of the proximal apertures or channels and in the bottom of thelower (distal) apertures. The pin could be a single device that isflipped over for placement in either the upper or the lower apertures.The dual head pin could be labeled or color-coded to indicate the offset side. For example, FIG. 3C shows ribbing 355 on the side of the pinhead offset for easy identification by a user.

In an embodiment where there are no end apertures and the at least twochannels are elongated from the proximal area to the distal area, anaperture may be present in a central midline position between thechannels. This central aperture may be used to provide minimal fixationof the plate without significant bone disruption during the initialplacement of the plate for sizing. Once a pin is in place in the centralaperture, differently sized plates could be placed on the pin toascertain the correctly sized plate for that patient. Once the plate isselected, temporary dual-headed pins could be used to anchor the platedistally and proximally by putting in a pin at each end of the channels.The cross-linking elements and attachment elements such as bone screwscan then be used to completely anchor the device to the vertebralbodies. The pins may be removed when the screws which replaced them areto be provided. Translational movement is possible with a plate havingelongated channels without end apertures.

Once a compatible plate and attachment elements are determined, theplate may be attached to the selected vertebrae by providing temporarypin placements or by providing screws through the plate apertures toaffix the plate at least at one end. The plate may be affixed to atleast two vertebrae by providing screws through the distal and proximalend apertures, or by providing other attachment elements. The screws mayfollow a tract made by the placement and removal of a temporary pin, orone of the heads of a dual-headed pin. One or more attachmentcross-links are added to the plate by providing temporary pins followedby screws or screws only or other fasteners only, through the attachmentcross-link, through the channels of the plate and into the vertebralbone. Spacer cross-links are added to the plate, around the attachmentcross-links, if necessary, or at least enough spacer cross-links areadded to substantially cover the channels. The spacer cross-links may beattached by screws, spring loaded clamps, or other locking components.Once all of the determined attachment cross-links and spacer cross-linksare added to the plate, the device is fully assembled and the surgicalsite may be closed.

Referring now in detail to the drawing figures, wherein like referencenumerals represent like parts throughout the several views, FIG. 1Aillustrates an exemplary embodiment of a plate 110 of an anteriorcervical instrumentation system 100. The plate 110 may be substantiallyflat, as shown, or curved, not shown, and may have a thickness rangingfrom 1-3 millimeters (mm). In an embodiment, the plate 110 may be 2 mmthick. The plate 110 may be rectangular in shape, having a proximal anddistal end. The plate 110 may measure 12-120 mms in length and 14-18 mmsin width. In an embodiment, the plate 110 may be approximately 18 mmslong and approximately 16 mms wide. The edges and corners of the plate110 may be square, or rounded or smoothed to reduce potential damage ortrauma to surrounding bone and/or tissue when implanted.

The plate 110 is adapted to be implantable in the human body, forexample, on the cervical portion of the spine. The plate 110 may becomposed of a suitable biocompatible or sterilizable material such asstainless steel, titanium, titanium alloys, memory alloys, nitinol,amorphous metal alloys, plastic, ceramic compounds, polymer compounds,carbon fiber, or another suitable material. The plate may be texturized,treated or coated on a portion or all of one or more sides to aid injoining of component parts, for bone growth or enhancement, to provideantimicrobial function, or immune response control.

The plate 110 may comprise a first aperture 120 a and a second aperture120 b, both disposed at the proximal end of the plate 110. The radius ofthe apertures 120 a and 120 b may be between 4-6 mms. In an embodiment,the radius of the apertures 120 a and 120 b may be approximately 4.6mms. The radius of the apertures 120 a and 120 b may correspond to thediameter of bone screws that will be used to secure plate 110 to thebone at a target site. The distance between the centers of the aperture120 a and 120 b may be between 6-12 mms. In an embodiment, the distancebetween the centers of the aperture 120 a and 120 b may be approximately9 mms. The plate 110 may further comprise a third aperture 120 c and afourth aperture 120 d disposed at the distal end of the plate 110. Thedimensions and arrangement of the third and fourth apertures 120 crelative to the plate 110 may be substantially identical to the firstand second apertures 120 a and 120 b.

The interior perimeters of the apertures 120 a-d may be substantiallycylindrical. In such embodiments, the apertures 120 a-d are adapted tointerface with a round head surgical screw or fastener. The head of sucha fastener may extend above the surface of the plate 110 when threadedthrough one of the apertures 120 a-d. This may not be optimal insituations where a minimal profile of the plate 110 and system 100 isdesired. In other embodiments, at least a portion of the interiorperimeter of the apertures 120 a-d may be frusto-conical. In suchembodiments, the apertures 120 a-d may be adapted to interface andreceive the angled surface of a flat head surgical screw or fastener.The head of such a fastener would be flush with the surface of the plate110 when threaded though one of the apertures 120 a-d.

In exemplary embodiments of the plate 110, the interior perimeter of theapertures 120 a-d may be substantially smooth. The apertures 120 a-d maybe substantially wide enough to enable the entire width of the fastener,including the treads, to pass through. In such embodiments, the plate110 would be secured to the surface of the bone at least partial due tothe compression caused by tightening the screw or fastener. In othercontemplated embodiments, the interior perimeter of the aperture 120 a-dmay be counter-threaded to correspond to the threading on a selectedscrew or fastener. In such embodiments, the fastener may be threadedthrough apertures 120 a-d and engage the bone to provide a secureattachment of the plate 110 to the vertebrae.

The plate 110 may further comprise a first channel 130 a and a secondchannel 130 b. The first and second channels 130 a and 130 b span thethickness of the plate 110 to provide elongated openings in the plate.The first and second channels 130 a and 130 b are elongate and extend inthe distal-proximal direction. The first channel 130 a may be disposedbetween and axially aligned with the first and third apertures 120 a and120 c. Similarly, the second channel 130 b may be disposed between andaxially aligned with the second and fourth apertures 120 b and 120 d.

The channels 130 a and 130 b may be adapted to receive a fastenersubstantially similar to the fasteners used to secure plate 110 to thevertebrae through apertures 120 a-d as described above. The width of thechannels 130 a and 130 b may be substantially equal to the width ofapertures 120 a-d. The length of the channels 130 a and 130 b may bebetween 14-100 mms. In an embodiment, the length of the channels 130 aand 130 b may be approximately 20 mms. The channels 130 a and 130 b maybe centered between apertures 120 a-d such that the ends of the channels130 a and 130 b are equidistant from the nearest aperture 120 a-d.

The interior perimeter of the channels 130 a-130 b may be substantiallysmooth. This may enable the body of a fastener passing through thechannels 130 a-130 b to smoothly translate in the distal to proximaldirection. This feature allows for the attachment cross-links elements,described below, to “float” relative to the plate 110.

The plate 110 may be adapted to attach to vertebrae using temporarypins, surgical screws or fasteners as described above as attachmentelements. In particular, the plate 110 is adapted to be disposed on theanterior side of the cervical portion of the spinal column. In othercontemplated embodiments, the plate 110 may by used in other regions ofthe spinal column or other bones of the body.

FIG. 1B shows exemplary plates wherein the distal and proximal endapertures 120 e-h are elongated, or wherein the proximal apertures 120i,j are elongated and the distal apertures 120 k,l are round. Forelongated apertures, the vertical length of the aperture may be 6-8 mm.The apertures and channels 130 c,d may be as described in FIG. 1A.

FIG. 1C shows an exemplary plate wherein the channels 130 g and 130 hare located substantially from near the proximal end of the plate 110 tonear the distal end of the plate 110, and provide an opening from theanterior to the posterior sides of the plate 110. There are no endapertures. A central midline aperture 120 m is shown as an elongatedaperture, but may be a round or other shaped aperture (not shown). Theplate, aperture and channels may be as described for FIGS. 1A and 1B.

FIG. 1D illustrates a side view of an exemplary embodiment of a plate110 attached to a region of the spinal column. The plate 110 may beattached to a first vertebra 150 a by means of fasteners threadedthrough the first and second apertures 120 a and 120 b and engaging thebone. Because the depiction is a side view, it is difficult todistinguish in the illustration between the first and second aperturesas one is directly behind the other. Further, the channels 130 a and 130b are not depicted in the drawing.

The plate 110 may be positioned such that the proximal end is directlyabove the first vertebra 150 a. The surgeon may maneuver the plate 110such that the first and second apertures 120 a and 120 b are directlyover a target drill site, or a site for placement of a dual-headed pin,or two pins. The surgeon may mark the drill sites, remove the plate 110,and use a guide to drill holes of the appropriate depth at the targetdrill sites. Alternatively, the surgeon may leave the plate in place andeither use the plate as a drill guide or place a drill guide atop theplate to drill the necessary holes. Alternatively, the surgeon may leavethe plate in place and provide a dual-headed pin through both apertures120 a and 120 b simultaneously. A dual-headed pin or two pins may beplaced through apertures 120 c and 120 d. One of the dual-headed pins isthen removed, and the surgeon may then attach the plate 110 to the firstvertebra using the selected screw or fastener. The other dual-headed pinor two pins are removed, and screws are placed through the plateapertures and into the bone.

The above process may be substantially repeated to attach the distal endof the plate 110 to a second vertebra 150 b. This will lock the firstand second vertebrae 150 a and 150 b in position relative to each other.The first and second vertebrae 150 a and 150 b are preferably onopposite sides of a target vertebra 150 c or vertebrae undergoingtreatment. The vertebra 150 c undergoing treatment may be attached tothe plate 110 using cross-linking elements, as will be described below.

Given the differences in anatomy and injuries between patients, andnumber of vertebrae undergoing treatment, the distance between suitableattachment sites on the first and second vertebrae may differsubstantially from the distance between the first and second apertures120 a and 120 b at the proximal end of the plate 110 and the third andfourth apertures 120 c and 120 d at the distal end. To enable optimalfitment, the system 100 may comprise a plurality of plates of variablelengths.

FIG. 2 illustrates an exemplary embodiment of a system having aplurality of plates. In this exemplary embodiment, the system 200 maycomprise a first plate 210 a, a second plate 210 b, and a third plate210 c. The plates 210 a-c may be substantially identical in design anddimension to plate 110 with the exception of the overall length of theplates and the elongate channels. Alternatively, a system may compriseplates of differing lengths as shown in FIG. 2, but plates in each sizemay have differently shaped apertures, or a central aperture, and/orchannels are exemplified in FIGS. 1A-C.

The plates 210 a-c each may have a different length. In one embodiment,the difference between the lengths of the plates may be in an incrementsubstantially equal to the height of a vertebra. In such an embodiment,the first plate 210 a could be intended to attach to a first and secondvertebra, as described above, which have three target vertebraeundergoing treatment located there between. The second plate 210 b couldbe adapted to be used when two vertebrae are undergoing treatment.Similarly, the length of the third plate 210 c could make it suitablefor situations where a single vertebra is undergoing treatment.

In other embodiments, the difference in length between the plates 210a-c may correspond to the difference in lengths between desirabledrilling sites on the vertebra of patients. For example, plates 210 a-ccould be similar in length and adapted for use in situations where asingle vertebra is undergoing treatment. The differences in the lengthof plates 210 a-c could correspond to the difference in the size ofvertebra of patients. This would enable a surgeon to intraoperativelyselect the appropriate length plate to attach to the vertebra of apatient.

In other contemplated embodiments, the plates 210 a-c could have a widerange of lengths accounting for both applications with one or moretarget vertebra and vertebra of different sizes. In such embodiments,the system 200 may comprise more plates that the three illustrated. Forexample, the plates may incrementally vary in length to span anoperational range from the shortest to the longest plate that mayfeasibly be used.

FIG. 3A illustrates embodiments of cross-linking elements. Thecross-linking element 340 may be constructed from the same material asthe plate 110 described above. The cross-linking element 340 may besubstantially equal in length to the width of plate 110. The width ofthe cross-linking element 340 may be between 14-18 mms. In anembodiment, the cross-linking element may be 16 mm wide. The thicknessof the cross-linking element 340 may be between 1-3 mms. In anembodiment, the cross-link may be 2 mm thick.

The cross-linking element 340 may comprise a first aperture 341 a and asecond aperture 341 b. The dimensions and distance between apertures 341a and 341 b may be substantially similar to those of apertures 120 a and120 b.

The interior perimeters of the apertures 341 a and 341 b may besubstantially cylindrical. In such embodiments, the apertures 341 a and341 b are adapted to interface with a round head surgical screw orfastener. In other embodiments, a portion of the interior perimeter ofthe apertures 341 a and 341 b may be frusto-conical. In suchembodiments, the apertures 341 a and 341 b may be adapted to interfaceand receive the angled surface of a flat head surgical screw orfastener.

In exemplary embodiments of cross-linking element 340, the interiorperimeter of the apertures 341 a and 341 b may be substantially smooth.The apertures 120 a-d may be substantially wide enough to enable theentire width of the fastener, including the threads, to pass through. Inother contemplated embodiments, the interior perimeter of the aperture341 a and 341 b may be counter-threaded to correspond to the treads on aselected screw or fastener.

The cross-linking element 360 may be constructed from the same materialas the plate 110 described above. The cross-linking element 360 may besubstantially equal in length to the width of plate 110. The width ofthe cross-linking element 360 may be between 14-18 mms. In anembodiment, the cross-linking element may be 16 mm wide. The thicknessof the cross-linking element 360 may be between 1-3 mms. In anembodiment, the cross-linking element may be 2 mm thick.

The cross-linking element 360 may comprise a first aperture 361 a and asecond aperture 361 b. The dimensions and distance between apertures 361a and 361 b may be substantially similar to those of apertures 120 a and120 b.

The cross-linking element 370 may be constructed from the same materialas the plate 110 described above. The cross-linking element 370 may besubstantially equal in length to the width of plate 110. The width ofthe cross-linking element 370 may be between 14-18 mms. In anembodiment, the cross-linking element may be 16 mm wide. The thicknessof the cross-linking element 370 may be between 1-3 mms. In anembodiment, the cross-linking element may be 2 mm thick.

The cross-linking element 370 may comprise a first aperture 371 a and asecond aperture 371 b. The dimensions and distance between apertures 371a and 371 b may be substantially similar to those of apertures 120 a and120 b.

FIG. 3B shows an exemplary dual-headed pin 350. The pin has two pinheads 351 and 352, and a handle 353. The pin heads may be from 12-20 mmand a system may comprise one or more dual-headed pins having at leastone of each of the 12-20 mm lengths. The handle 353 may be of any lengththat is suitable for holding or tapping by the surgeon.

FIG. 4A illustrates a top view of a plate and cross-linking elements ofan exemplary embodiment of the system. In an exemplary embodiment, thesystem 400 may comprise a plate 410 having apertures 420 a-d, andcross-links. The plate 410 and cross-linking elements may besubstantially similar to the plates and cross-linking elements describedabove. Cross-linking elements may be employed either as a spacercross-link or as an attachment cross-link. In an embodiment, the system400 comprises attachment cross-link 440 and 470, a first spacercross-link 450, and a second spacer cross-link 460.

The attachment cross-link 440 may be coupled to the plate 410 bythreading fasteners through apertures 441 a and 441 b and channels 430 aand 430 b, and engaging the vertebra disposed below the plate. In anembodiment, the attachment cross-link 440 is not fixed in positionrelative to plate 410. Rather, attachment cross-link 440 may move atopthe plate 410 as the fasteners glide though channels 430 a and 430 b.

The attachment cross-link 470 may be coupled to the plate 410 bythreading fasteners through apertures 471 a and 471 b and channels 430 aand 430 b, and engaging the vertebra disposed below the plate. In anembodiment, the attachment cross-link 470 is not fixed in positionrelative to plate 410. Rather, attachment cross-link 470 may move atopthe plate 410 as the fasteners glide though channels 430 a and 430 b.

Spacer cross-links 450 and 460 may be disposed on both sides of theattachment cross-link 440 and proximal to cross-link 470 to limit theirdegrees of motion. In an exemplary embodiment, the first spacercross-link 450 may be attached to the plate 410 on the proximal side ofthe attachment cross-link 440. The second spacer cross-link 460 may beattached on the distal side of the attachment cross-link 440, andproximal to attachment cross-link 470. The spacer cross-links 450 and460 may be attached to the plate 410 using a fastener, such as a hole tohole clamp, a screw head, or short screw, by means of channels 430 a and430 b and apertures 451 a, 451 b, 461 a, and 461 b. The spacercross-links 450 and 460 may be fixed in position relative to the plate410 upon attachment to the plate. In other contemplated embodiments, thespacer cross-links 450 and 460 may be spring loaded or employ springloaded fastening elements to attach to the plate 410. There are multipledifferent spring loaded fastening elements known in the art and thedecision for which fastening elements to use is within the knowledge ofthose skilled in the art.

The attachment position of spacer cross-links 450 and 460 may beselected to limit the range of motion of the attachment cross-links 440and 470 as desired. The cross-links minimize rotational movement. Uponcoupling to the plate 410, spacer cross-links 450 and 460 define how farattachment cross-links 440 and 470 may move along the plate 410 onchannels 430 a and 430 b, as illustrated by the dashed arrows.

FIG. 4B illustrates a top view of a plate and cross-linking elements ofan exemplary embodiment of the system. In an exemplary embodiment, thesystem 410 may comprise a plate 410 having only a central aperture 420e, two channels that are located from an area near the proximal end toan area near the distal end, and cross-linking elements. The plate 410and cross-linking elements may be substantially similar to the platesand cross-linking elements described above. Cross-linking elements maybe employed either as a spacer cross-link or as an attachmentcross-link. In an embodiment, the system 410 comprises attachmentcross-links 445, 475 and 490, and spacer cross-links 455, 465 and 480.

The attachment cross-links 445, 475 and 490 may be coupled to the plate410 by threading fasteners through apertures 446 a and 446 b, 476 a and476 b, 491 a and 491 b, respectively, and through channels 435 a and 435b, and engaging the vertebrae disposed below the plate. In anembodiment, the attachment cross-links 445, 475 and 490 are not fixed inposition relative to plate 410. Rather, attachment cross-link 445, 475and 490 may move atop the plate 410 as the fasteners glide thoughchannels 435 a and 435 b.

Spacer cross-links 455, 465 and 480 may be disposed on the plate 410 tolimit the degrees of motion of attachment cross-links 445, 475 and 490.In an exemplary embodiment, spacer cross-link 455 may be attached to theplate 410 on the proximal side of the attachment cross-link 445. Spacercross-link 465 may be attached on the distal side of the attachmentcross-link 445, and proximal to attachment cross-link 475. Spacercross-link 480 may be attached on the proximal side of the attachmentcross-link 490. The spacer cross-links 455, 465 and 480 may be attachedto the plate 410 using a fastener, such as a hole to hole clamp, a screwhead, or short screw by means of channels 435 a and 435 b and apertures456 a, 456 b, 466 a, and 466 b, 481 a and 481 b, respectively. Thespacer cross-links 455, 465 and 480 may be fixed in position relative tothe plate 410 upon attachment to the plate. In other contemplatedembodiments, the spacer cross-links 455, 465 and 480 may be springloaded or employ spring loaded fastening elements to attach to the plate410. There are multiple different spring loaded fastening elements knownin the art and the decision for which fastening elements to use iswithin the knowledge of those skilled in the art.

The attachment position of spacer cross-links 455, 465 and 480 may beselected to limit the range of motion of the attachment cross-links 445,475 and 490 as desired. The cross-links minimize rotational movement.Upon coupling to the plate 410, spacer cross-links 455, 465 and 480define how far attachment cross-links 445, 475 and 490 may move alongthe plate 410 on channels 430 a and 430 b, as illustrated by the dashedarrows. The attachment cross-links are also limited in movement by theends of the channels 435 a and 435 b.

In other contemplated embodiments, multiple attachment cross-links couldbe used with a multiple spacer cross-links. For example, a spacercross-link could be attached to the middle of the plate and attachmentcross-links placed on either side. The ends of the channels 435 a and435 b and the spacer cross-link would limit the range of motion of theattachment cross-links. In other embodiments, various configurations andspacer and attachment cross-links are contemplated to attain a desirableresult for a particular application.

FIG. 5 illustrates a side view of an exemplary embodiment of the device500 and system attached to a spinal column. Plate 510 may be attached toa first vertebra 550 a and a second vertebra 550 b in substantially thesame manner as plate 110 described above, using fasteners throughapertures 520 a-d. The attachment cross-link 540 may be placed atopplate 510 and attached to the a target vertebra 550 c by passing afastener 580 through the apertures of the cross-link 540 and channels(not pictured) of the plate 510 and engaging with a hole in the vertebra550 c.

Spacer cross-links 550 and 560 may be attached to the plate in a fixedposition as described above. The attachment cross-link 540 may movealong plate 510 as the fasteners glide through the channels of the plate510. The movement of the attachment cross-link 540 is limited by thespacer cross-links 550 and 560. Attachment cross-link 540 may moveupward until it comes in contact with the first spacer cross-link 550.Similarly, attachment cross-link 540 may move downward until it comes incontact with the second spacer cross-link 560.

Movement of attachment cross-link 540 enables the target vertebra 550 cto move up and down, relative to the first and second vertebrae 550 aand 550 b. This movement or subsidence allows for bone-to-bone contact.

FIG. 6A illustrates a top view of a vertebral stabilization device 600that can comprise plate 610 and attachment cross-links 650 and 660 in anembodiment of the present invention. The elongate plate 610 can have adistal end and a proximal end and can have an anterior side and aposterior side and can be adapted to be implantable in the human body,for example, on the cervical portion of the spine. The elongate plate610 can comprise a plurality of channels 630 a-630 b that can beconfigured to be coupled with attachment cross-link 650 and a fastener640 such that the plate is coupled to two or more vertebra. Thus, theplate can stabilize the vertebra after surgery.

In one embodiment, the plate 610 can comprise a first elongate channel630 a and a second elongate channel 630 b. The channels 630 a and 630 bcan extend along at least a portion of the plate between the distal endand the proximal end. In one embodiment, the first elongate channel 630a and the second elongate channel 630 b can be substantially parallel.In an embodiment, the first elongate channel 630 a and the secondelongate channel 630 b can span the thickness of the plate 610 toprovide openings in the plate 610. In embodiments where the elongatechannels 630 span the thickness of the plate 610, attachment cross-links650 and 660 can be placed at various points along the channels viacoupling of the attachment cross-links 650 and 660 to the channels 630through cross-link grooves and channel grooves 670 a-670. This canprovide a customizable, modular device that can be modifiedintra-operatively as the surgeon desires.

The channels 630 a-630 b can be adapted to receive a fastener 640through an aperture 651 a-b and 661 a-b in the attachment cross-links650 and 660 in order to secure the plate 610 to the vertebra. Forexample, the fastener can extend through an aperture in the cross-linkand into a verterbra of a patient, thereby securing the device to thepatient.

The channels 630 a-630 b can comprise an interior surface comprising aplurality of channel grooves 670 a-670 b disposed on at least a portionof the interior surface. In other embodiments, the channels 630 a and630 b may include other attachment features to cross-link in a desiredposition along the plate 610. The interior surface can also besubstantially smooth on at least a portion of the interior surface. Insome embodiments, the channel grooves 670 a can be disposed on theanterior side of elongate channel 630 a and the channel grooves 670 bcan be disposed on the posterior side of the elongate channel 630 b. Thechannel grooves 670 a-670 b can provide a means of engaging theattachment cross-links 650 and 660 to the plate 610, thereby securingthe cross-links in a position along the plate 610.

The plate 610 can further comprise attachment cross-links 650 and 660that can be configured to couple plate 610 to the vertebra. In oneembodiment, the plate 610 can comprise a first attachment cross-link 650and a second attachment cross-link 660. Several attachment cross-linkscan be used in order to provide multiple stabilization points. Theattachment cross-links 650 and 660 can comprise a plurality ofcross-link grooves on the outer surface of the cross-links. Thecross-link grooves can be configured to cooperatively engage the channelgrooves 670 a-670 b.

The attachment cross-links 650 and 660 can comprise a plurality ofapertures 651 a-651 b and 661 a-661 b, respectively. In an embodiment,the attachment first attachment cross-link 650 can have a first aperture651 a and a second aperture 651 b. In one embodiment, the secondattachment cross-link 660 can comprise a third aperture 661 a and afourth aperture (not shown).

Apertures 651 a-b and 661 a-b can be configured to be aligned with thefirst and second elongate channels. Attachment cross-links 650 and 660can be coupled to the plate 610 by one or more threaded fasteners 640through apertures 651 a-651 b and 661 a-661 b and through channels 630 aand 630 b, and engaging the vertebra disposed below the plate. Theapertures 651 a-651 b can be substantially wide enough to enable a widthof a fastener 640, including threads, to pass through. In an embodiment,the attachment cross-links 650 and 660 are not fixed in positionrelative to plate 610. Rather, attachment cross-links 650 and 660 canmove atop the plate 610 as the fasteners glide through channels 630 aand 630 b. In some embodiments, all of the attachment cross-links 650and 660 are fixed. In other embodiments, all of the attachmentcross-links are dynamic relative to plate 610. Some embodiments ofdevice 600 comprise both dynamic and fixed attachment cross-links 650and 660.

FIG. 6B illustrates attachment cross-links 650 and 660 according to anembodiment of the present invention. As described above, an embodimentof the present invention can comprise an attachment cross-link 650-660that can be configured to couple to the elongate plate 610 and tothreading fasteners through apertures 651 a-651 b and 661 a-661 b andthe channels, and engage the vertebra disposed below the plate 610. Insome embodiments, the apertures can comprise a c-clip spacer 652 a-b and662 a-b substantially within an interior volume of the aperture. Thec-clip spacer 652 a-b and 662 a-b can be configured to serve as aspacer/seal between a surface of a crosslink and a surface of afastener. In an embodiment, the apertures 651 a-651 b and 661 a-661 bcan comprise female helical threads adapted to receive threadingfasteners through the apertures.

In an embodiment of the present invention, the attachment cross-links650 and 660 can further comprise an alignment guide, 653 and 663,configured to define a fastener placement angle. The alignment guide cancomprise an indicator 653 and 663. In some embodiments, the indicator653 and 663 can comprise a notch in an outer surface of the attachmentcross-link. The alignment guide can comprise many different indicatorsknown in the art including, but not limited to, a notch, an arrow, anindentation, a bump, a dot, and the like.

In an embodiment of the present invention, the attachment cross-link 650can be dynamic and move along the elongate channel. In an embodimentwhere the attachment cross-link can be dynamic and move along theelongate channel, there may not be channel grooves on the interiorsurface of the elongate channels. Similarly, there may not be cross-linkgrooves on the outer surface of the attachment cross-links, thusallowing the attachment cross-link to move dynamically along theelongate channel.

Alternatively, the attachment cross-link 650 can be static, or fixed,with respect to the elongate channel. The cross-link 650 can be fixed byengaging the attachment cross-link grooves 654 with the channel groovesfor fixation. In some embodiments, the elongate plate 610 can compriseboth dynamic and static attachment cross-links. In an embodiment, theelongate plate can comprise two or more attachment cross-links 650 and660 that can be dynamically coupled to the plate 610 with the endattachment cross-links being statically coupled to the plate, thusallowing the center vertebrae to be optimally fixed by adjusting theposition of the dynamic attachment cross-links.

In an embodiment of the present invention, the pull out strength of theplate 610 can be strong enough that once the fasteners are engaged tothe vertebrae, the cross-links and fasteners cannot easily be pulledaway from the plate itself and the vertebral body.

FIG. 6C illustrates a plate 610 in an exemplary embodiment of thepresent invention. In an embodiment of the present invention, theelongate channels 630 a and 630 b can be substantially equal in length.The elongate channels 630 a-630 b can extend substantially from thedistal end to the proximal end of the elongate plate 610. In someembodiments, the elongate channels 630 a and 630 b can continuouslyextend substantially from the distal end to the proximal end of theelongate plate 610. In an embodiment, the elongate channels 630 a-630 bcan comprise channel grooves 670 a and 670 b disposed on at least oneside of an interior surface of the channel 630 a and 630 b for engagingcorresponding grooves on the cross-links. In an embodiment, the elongateplate 610 can have an anterior side and a posterior side. In anembodiment, the posterior elongate channel 630 b can comprise channelgrooves 670 b disposed on the posterior side of the interior surface ofthe posterior elongate channel 630 b and the anterior elongate channels630 a can comprise channel grooves 670 a disposed on the anterior sideof the interior surface of the anterior elongate channel 630 a.

The elongate plate 610 can be various shapes suitable for extendingbetween vertebrae, such as, but not limited to, rectangular, square,oval, trapezoidal, circular, and the like.

In an embodiment of the present invention, the plate 610 can have athickness from about 0.5 mm to about 5 mm. In some embodiments, theplate 610 can have a thickness from about 1 mm to about 4 mm. In anembodiment, the plate 610 can have a thickness from about 1.5 mm toabout 3 mm. In an embodiment, the plate 610 can have a thickness fromabout 1.8 mm to about 2.2 mm. In one embodiment, the plate 610 can havea thickness from about 2 mm to about 2.25 mm. In an embodiment, theplate 610 can have a thickness of about 2 mm. In another embodiment, theplate can have a thickness of about 2.25 mm.

In an embodiment of the present invention, the elongate channels 630 aand 630 b may have a length suitable for positioning cross-link membersadjacent various vertebrae. In an embodiment of the present invention,the elongate channels 630 a and 630 b can have a length from about 3 mmto about 10 mm. In some embodiments, the elongate channels 630 a and 630b can have a length from about 4 mm to about 8 mm. In an embodiment, theelongate channels 630 a and 630 b can have a length from about 5 mm toabout 7 mm. In an embodiment, the elongate channels 630 a and 630 b canhave a length from about 5.5 mm to about 6.5 mm. In an embodiment, theelongate channels 630 a and 630 b can have a length of about 6 mm.

The elongate plate 610 can further comprise a distal aperture 620 a anda proximal aperture 620 b. The apertures 620 a-620 b can be configuredto fix the distal and proximal ends of the plate. The center vertebraecan be optimally fixed by adjusting the position of the attachmentcross-links. In an embodiment of the present invention, the elongatechannels 630 a and 630 b can extend substantially from the distalaperture to the proximal aperture.

FIG. 6D illustrates a bottom view of the vertebral stabilization device600 of the present invention. In an embodiment of the present invention,the attachment cross-links 650 and 660 are flush with the top surface ofthe plate 610. In some embodiments, the elongate channels 630 a-630 bcan further comprise a recessed portion disposed therein configured tobe in communication with the attachment cross-links 650 and 660 suchthat the attachment cross-links 650 and 660 can be flush with the topsurface of plate. In an embodiment, the attachment cross-links 650 and660 are not flush with the top surface of the plate.

FIG. 7A illustrates a top view of a vertebral stabilization device 700that can comprise plate 710 and a plurality of channels 730 a-730 f. Theelongate plate 710 can have a distal end and a proximal end and can havean anterior side and a posterior side. In an embodiment, the plate 710can comprise a first elongate channel 730 a and a second elongatechannel 730 b. In an embodiment, the plate 710 can further comprise athird elongate channel 730 c and a fourth elongate channel 730 d. Thechannels 730 a-730 b can extend along at least a portion of the platebetween the distal end and the proximal end. In an embodiment, the first730 a and second 730 b elongate channels can be substantially parallel.The third 730 c and fourth 730 d elongate channels can also besubstantially parallel.

Other contemplated embodiments can comprise a fifth elongate channel 730e and a sixth elongate channel 730 f, or more, with correspondingattachment cross-links, 750 and 760, for example, according to thenumber of channels disposed within the plate. In some embodiments, therecan be one attachment cross-link corresponding to every two elongatechannels. In some embodiments, there can be a plurality of attachmentcross-links corresponding to every two elongate channels.

FIG. 8 illustrates a top view of a vertebral stabilization device 800comprising extension adapter 880. An embodiment of the present inventioncan comprise an extension adapter 880 configured to allow adjacent levelincorporation without removal of the plate 810 during a revision. At thetime of revision, the distal or proximal attachment cross-link can beremoved and the extension adapter cross-links 885 and 886 can be engagedwith the plate 810. In an embodiment, the extension adapter 880 cancomprise a plurality of extension adapter cross-links 885 and 886. Theextension adapter 880 can be configured to couple to the plate 810 viathe extension adapter cross-links 885 and 886 and by threading fastenersthrough apertures 881 a-881 b and 891 a-891 b and channels 830 a-830 b,and engage the vertebra disposed below the plate 810. The plurality ofextension adapter cross-links 885 and 886 can be configured similarly toother attachment cross-links described above. In an embodiment of thepresent invention, the extension adapter cross-links can be static. Inembodiments where the extension adapter cross-links are static, theadapter cross-links can comprise grooves that can be configured tocooperatively engage the channel grooves of the elongate channels.

In an embodiment, the adapter cross-links can be dynamic and move alongthe elongate channels. In embodiments where the extension adaptercross-links are dynamic, the adapter cross-links may not compriseadapter grooves. Additionally, the elongate channels may not comprisechannel grooves in embodiments where the adapter cross-links aredynamic.

In some embodiments, the apertures 881 a-881 b and 891 a-891 b cancomprise a c-clip spacer substantially within an interior volume of theaperture. In an embodiment, the apertures 881 a-881 b and 891 a-891 bcan comprise female helical threads adapted to receive threadingfasteners through the apertures.

In an embodiment, the extension adapter 880 can have the same thicknessas the plate 810 and therefore can have substantially the same profileas the plate 810. The extension adapter 880 can comprise a bridge 895that connects the adapter 880 to the plate 810. In an embodiment, thebridge 895 can have a thickness less than the thickness of the extensionadapter cross-links 885 and 886 such that the overall plate height canbe equal between the main plate 810 and the extension adapter 880. Insome embodiments, the bridge 895 can have a thickness from about 0.5 mmto about 1.2 mm. In some embodiments, the bridge 895 can have athickness from about 0.7 mm to about 1.0 mm. In an embodiment, thebridge 895 can have a thickness of about 0.8 mm.

It should be apparent to those skilled in the art to which thisdisclosure pertains that there are several advantages to the devices andmethods disclosed herein. In general, the device provides one system forboth simple and complex cases. Additionally, a surgeon can change from astatic to a dynamic plate easily depending on the situation.Furthermore, the device can also be a hybrid type plate, that is, withboth static and dynamic capabilities. The dynamic movement of theattachment cross-links to fix the center vertebrae can allow the surgeonto have maximal flexibility in placing the intervening cross links whilethe end cross links can be static or dynamic. A further advantage of theplate is that it can be easily assembled once the surgeon has estimatedthe length needed. Additionally, the device of the present invention canbe inexpensive to manufacture, simple to use and require minimalinventory for doctor's offices and/or hospitals. It can also beadjustable for complex reconstructions and allow for intra-operativeflexibility.

The various embodiments described above are intended to enable a surgeonto intraoperatively customize the anterior cervical instrumentationsystem for optimal application. Consequently, the embodiments describedabove are merely exemplary and not limiting. In particular, theconfigurations, dimensions and orientation of components described abovemay be modified from what has been recited and described withoutdeparting from the design of the invention. Further, embodiments of thepresent invention are not limited to applications in the anterior regionof the spine. Particularly, the embodiments of the present invention canalso be used in the thoracic and lumbar regions.

What is claimed is:
 1. A vertebral stabilization device comprising: anelongate plate, the plate having a distal end and a proximal end, theplate comprising a first elongate channel and a second elongate channel,the first and second elongate channels being substantially parallel andextending along at least a portion of the plate between the distal endand the proximal end, wherein each of the first and second elongatechannels have an interior surface, at least a portion of the interiorsurfaces comprising a plurality of channel grooves; and a firstattachment cross-link, the first attachment cross-link having a firstaperture and a second aperture, the first and second aperturesconfigured to be aligned with the first and second elongate channels;wherein at least a portion of at least one outer surface of the firstattachment cross-link comprises a plurality of cross-link groovesadapted to cooperatively engage the plurality of channel grooves of theinterior surface of at least one of the first and second elongatechannels.
 2. The device of claim 1, further comprising: a third elongatechannel and a fourth elongate channel, the third and fourth elongatechannels being substantially parallel and extending along at least aportion of the plate between the distal end and the proximal end,wherein the third and fourth elongate channels have an interior surface,at least a portion of the plate between the distal end and the proximalend, wherein each of the third and fourth elongate channels have aninterior surface, at least a portion of the interior surfaces comprisinga plurality of channel grooves; and a second attachment cross-link, thesecond attachment cross-link having a third aperture and a fourthaperture, the third and fourth apertures configured to be aligned withthe third and fourth elongate channels; wherein at least a portion of atleast one outer surface of the second attachment cross-link comprises aplurality of cross-link grooves adapted to cooperatively engage theplurality of channel grooves of the interior surface of at least one ofthe third and fourth elongate channels.
 3. The device of claim 1,further comprising: a fifth elongate channel and a sixth elongatechannel, the fifth and sixth elongate channels being substantiallyparallel and extending along at least a portion of the plate between thedistal end and the proximal end, wherein the fifth and sixth elongatechannels have an interior surface, at least a portion of the platebetween the distal end and the proximal end, wherein each of the fifthand sixth elongate channels have an interior surface, at least a portionof the interior surfaces comprising a plurality of channel grooves; anda third attachment cross-link, the third attachment cross-link having afifth aperture and a sixth aperture, the fifth and sixth aperturesconfigured to be aligned with the fifth and sixth elongate channels;wherein at least a portion of at least one outer surface of the thirdattachment cross-link comprises a plurality of cross-link groovesadapted to cooperatively engage the plurality of channel grooves of theinterior surface of at least one of the fifth and sixth elongatechannels.
 4. The device of claim 1, wherein the first and secondelongate channels are substantially equal in length.
 5. The device ofclaim 1, further comprising a distal aperture and a proximal aperture.6. The device of claim 3, wherein the elongate channels extendsubstantially from the distal aperture to the proximal aperture.
 7. Thedevice of claim 1, further comprising a spacer positioned substantiallywithin an interior volume of at least one of the first and secondapertures.
 8. The device of claim 1, wherein at least one of the firstor second apertures comprises female helical threads.
 9. The device ofclaim 1, wherein the attachment cross-link further comprises analignment guide for defining a fastener placement angle.
 10. The deviceof claim 9, wherein the alignment guide comprises a notch in an outersurface of the attachment cross-link.
 11. The device of claim 1, whereinthe first and second elongate channels continuously extend from theproximal end to the distal end of the plate.
 12. The device of claim 11,wherein the first and second elongate channels further comprise a secondattachment cross-link.
 13. The device of claim 2, wherein the third andfourth elongate channels extend from the distal end to the proximal endof the plate proximate a midpoint between the distal and proximal ends.14. A method for stabilizing a vertebral column comprising: disposing anelongate plate in an intervertebral space of a patient, the plate havinga distal end and a proximal end, the plate comprising an elongatechannel extending along at least a portion of the plate between thedistal end and the proximal end, wherein the elongate channel has aninterior surface, at least a portion of the interior surface comprisinga plurality of channel grooves; placing a first attachment cross-link onthe plate, an outer surface of the attachment cross-link comprising aplurality of attachment grooves adapted to cooperatively engage theplurality of channel grooves of the interior surface of the elongatechannel; and attaching the first attachment cross-link to a vertebraewith a fastener.
 15. A vertebral stabilization device comprising: anelongate plate, the plate having a distal end and a proximal end, theplate comprising a first elongate channel and a second elongate channel,the first and second elongate channels being substantially parallel andextending along at least a portion of the plate between the distal endand the proximal end; and a first attachment cross-link, the firstattachment cross-link having a first aperture and a second aperture, thefirst and second apertures configured to be aligned with the first andsecond elongate channels; wherein the first attachment cross-link isconfigured to move dynamically along at least a portion of the first andsecond elongate channels.